There are disk type governors and fly ball type governors as elevator governors which have hitherto been widely used. Overspeed detection mechanisms of conventional governors represented by these types of governors have no rotation direction dependence. For this reason, overspeed detection is performed at the same speed in all rotation directions.
However, for example, in a car-side governor of an elevator in which the ascent speed of a car is higher than the decent speed, an overspeed detection mechanism set so as to be adapted to the descent speed of the car operates also during the ascent of the car. For this reason, this has posed the problem that it is impossible to perform overspeed detection adapted to each of the ascent speed and the descent speed of the car.
In contrast to this, there have been proposed governors which are such that one governor is provided with two independent overspeed detection mechanisms having different detection operation speeds. In such governors, however, the rotation of a sheave is transmitted to an overspeed detection mechanism having a lower detection operation speed via a ratchet. On the other hand, the rotation of a sheave is not transmitted to the other overspeed detection mechanism having a higher direction operation speed, because the ratchet becomes free. As a result of this, in the car-side governor of an elevator in which the ascent speed of a car is higher than the descent speed, it is possible to carry out overspeed detection adapted to each of the ascent speed and the descent speed (refer to Patent Document 1, for example).
Patent Document 1: Japanese Patent Laid-Open No. 2000-327241